Harnessing Fungal Variety to Break Down Antibiotic Contaminants

Greg Howard
27th May, 2024

Harnessing Fungal Variety to Break Down Antibiotic Contaminants

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Université de Sfax studied the ability of ligninolytic fungi to break down ten fluoroquinolone antibiotics
  • Bjerkandera adusta and Porosterum spadiceum were the most effective, completely degrading eight and six antibiotics, respectively, within 15 days
  • The fungi used various mechanisms, including enzymatic routes and adsorption, to degrade the antibiotics, showing potential for environmental remediation
Antibiotics, particularly fluoroquinolones, play a crucial role in treating various infections in humans and animals. However, their widespread use has led to significant environmental concerns, primarily due to the emergence of antibiotic-resistant bacteria and the disruption of microbial ecosystems. A recent study conducted by researchers at Université de Sfax investigates the potential of ligninolytic fungi to biodegrade ten fluoroquinolone antibiotics, offering a promising solution to this environmental issue[1]. This study's findings are particularly relevant in light of previous research that has highlighted the environmental persistence and ecotoxicological effects of fluoroquinolones. For instance, fluoroquinolones have been detected in various ecosystems, where they contribute to the selection pressure on microorganisms, leading to multidrug-resistant bacteria[2]. The presence of the fluorine atom in fluoroquinolones makes them highly resistant to microbial degradation, posing a significant challenge for environmental remediation efforts. The study by Université de Sfax explored the biodegradation capabilities of several ligninolytic fungi, including Trametes versicolor, Bjerkandera adusta, Porosterum spadiceum, and others. These fungi were tested for their ability to degrade six fluoroquinolones used in medical treatments and four used in veterinary practices. The results showed significant variations in the efficiency of antibiotic transformation among the different fungal strains. Notably, B. adusta and P. spadiceum were the most effective, completely degrading eight and six antibiotics, respectively, within a 15-day period. T. versicolor and P. ostreatus also demonstrated substantial degradation capabilities, with T. versicolor degrading six out of ten antibiotics by more than 70%, and P. ostreatus achieving degradation rates between 43% and 100%. The study also delved into the mechanisms employed by these fungi to degrade fluoroquinolones. These mechanisms include enzymatic routes such as oxidation by laccases, heme-peroxidases, and cytochrome P450, as well as adsorption on fungal biomass. Interestingly, the remaining antibiotic activity did not always correlate with a reduction in antibiotic concentrations, suggesting the presence of post-transformation antimicrobial metabolites. These findings align with earlier studies that have documented the relationship between antibiotic consumption and resistance rates. For example, research conducted in Argentina demonstrated a direct correlation between the consumption of fluoroquinolones and carbapenems and the resistance rates of Pseudomonas aeruginosa[3]. Similarly, a study of 145 tertiary hospitals in China found a strong correlation between antibiotic consumption and the resistance rates of various gram-negative bacteria[4]. These studies underscore the importance of addressing antibiotic consumption to mitigate resistance rates, a goal that could be supported by the effective biodegradation of antibiotics in the environment. Moreover, data from 30 EU/EEA countries over two decades revealed significant seasonal variations in antibiotic consumption, which decreased over time[5]. This trend suggests that efforts to regulate antibiotic use are having a positive impact. However, the persistent presence of fluoroquinolones in the environment necessitates additional measures, such as the biodegradation strategies explored in the Université de Sfax study. In conclusion, the research conducted by Université de Sfax provides valuable insights into the potential of ligninolytic fungi to degrade fluoroquinolone antibiotics, offering a promising approach to mitigating the environmental impact of these persistent pollutants. By leveraging the natural biodegradation capabilities of fungi, we can address the challenges posed by antibiotic resistance and environmental contamination, complementing existing efforts to regulate antibiotic use and reduce resistance rates.

EnvironmentBiochemMycology

References

Main Study

1) Valorizing fungal diversity for the degradation of fluoroquinolones.

Published 30th May, 2024 (future Journal edition)

https://doi.org/10.1016/j.heliyon.2024.e30611

Related Studies

2) Fluoroquinolone antibiotics: Occurrence, mode of action, resistance, environmental detection, and remediation - A comprehensive review.

https://doi.org/10.1016/j.envpol.2022.120440

3) Association between Consumption of Fluoroquinolones and Carbapenems and Their Resistance Rates in Pseudomonas aeruginosa in Argentina.

https://doi.org/10.1155/2022/3924212

4) Association between the rate of fluoroquinolones-resistant gram-negative bacteria and antibiotic consumption from China based on 145 tertiary hospitals data in 2014.

https://doi.org/10.1186/s12879-020-04981-0

5) Consumption of antibiotics in the community, European Union/European Economic Area, 1997-2017.

https://doi.org/10.1093/jac/dkab172


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